Helplessly the two men hurtled down the snowy slope

For long moments they lay still. A thick pall of settling snow hung on the frigid air. The wind seized portions of this and sent them whirling and twisting in fantastic gyrations.

The thermalloy suits were essentially compact, mobile shelters, and had been designed more for protection against inimical extra-terrestrial elements rather than for comfort. Brad Nellon had been bruised and shaken until it seemed that his body was one throbbing ache. His senses whirled giddily in a black mist shot through with flames of pulsing red.

Of a sudden the pain leaped to intolerable heights. His battered muscles screamed an anguished protest along his nerves. Then the pain was gone, and momentarily the blackness closed in again. But something like a fresh wind sprang up, and sent the engulfing fog thinning away. Nellon's brain cleared. He opened his eyes.

He looked into Big Tim's face. Big Tim was bending over him, worried and anxious. Nellon began to understand.

Big Tim had recovered first from the plunge. He had propped Nellon up, then turned the valve which increased the flow of oxygen inside his suit. They were alive. Nellon felt a dull wonder at it.

"Brad—all right?" It was Big Tim, his voice strained and hoarse.

Nellon nodded mechanically.

"All right."

"What happened, Brad?"

Nellon looked away. He looked up the gorge, at the tip of Tower Point. He licked his lips.

"I—I don't know. Didn't feel well—slipped on a patch of ice."

Big Tim shook his head.

"I told you to stay up there, didn't I? I knew you were in no condition to make the descent, but you were just stubborn enough to do so. It's lucky we didn't get our necks broken." He looked down and across to where, directly under the falls, the ice fangs jutted, cruel and gleaming.

Nellon was fully recovered now. He followed the direction of Austin's gaze, and though his eyes saw the same thing, his mind pictured it in a different way.

Those ice teeth should have meant Big Tim's death. He, Nellon, had failed, had narrowly escaped losing his own life because of his blunder. Intent upon the shove which was to have sent Tim Austin hurtling to his death, he had forgotten the snow-concealed ice in the trail, as lethal with hidden treachery as a patch of quick-sand.

But he was still alive. They hadn't, as yet, even reached Ryska's hut, and Nellon knew another chance would present itself. He considered this with a curious mixture of impatience and reluctance.

"If it wasn't for Big Tim—" Nellon was hearing Laura say the words again, and once again the realms of unutterable bliss he read into them strengthened his resolve. One more chance—and this time he would not fail or waver.

"Brad—look!"

Vibrant with surprise and urgency, the words ripped aside the veil of Nellon's thoughts. His head jerked up.

Big Tim was on his feet. He was pointing up at the steep bank of the gorge down which they had tumbled.

Most of the disturbed snow had settled and the wind had carried away the rest. Nellon could see quite clearly.

There up on the bank, a small snow slide had taken place. And now, against the unbroken monotony of white, something gleamed in vivid contrast.

Nellon squinted. Gradually he began to make out details. The strange surface revealed by the slide seemed to have the mellow hue of bronze, but Nellon could not be sure, since it was queerly dappled and flecked with tones of gold and red. He thought it must be from the strain on his eyes, and closed them momentarily. But when he looked again the colors were as weird as he had last seen them. This time, however, he made out a detail which he had missed previously. The surface seemed to be crossed by a black line or stripe.

"Now what in the world can that be?" Tim Austin's voice was wondering, vaguely troubled. "It's like no sample of rock or soil we've taken. Metal—that's what it is!" he exclaimed of a sudden. "It's an exposed vein of some metal. Come on, Brad, let's have a look at it."

Nellon got to his feet, his eyes fixed upon that uncanny patch of something which stood out against the surrounding whiteness like a smear of blood.

Big Tim was already started up the bank. Nellon sucked in a breath and followed after him.

The climb was a hard and difficult one, and their recent physical jarring caused by the fall made it all the harder. But curiosity pulled them on like a vast magnet. In the exertion they forgot their aches and bruises. Slipping and sliding, clutching for handholds, floundering in loose drifts which filled pockets of hardened crust, they made their way slowly but surely up the bank.

Finally they stood before that strangely mottled patch of red and brown and gold. The mood of awed wonder which gripped them at once heightened and deepened.

"It is metal!" Tim Austin breathed. "But—but, Brad, it's not a vein. It's—"

"It's a door!" Nellon finished hoarsely.

It was a door, a metal door in the snow covered bank of a falls that had, in some long, long ago, solidified to ice. A door to what? Where did it lead? What would be on the other side of it? What could be on the other side of a metal door on a world where it was doubtful that living beings had ever existed at all?

There was a rasp in Nellon's earphones. And then Big Tim Austin's voice followed it.

"Brad—I'm going in. This—why, this is the biggest find of the whole expedition!"

"It might be dangerous," Nellon pointed out, before he could become aware of the wealth of irony which lay behind the words. "We don't know what sort of life—"

"But this door has been hidden under snow for the Lord only knows how many years, Brad. Look where the crust had split here. It's thick, thick. Nothing has gone in or out for a hell of a long time. If there were beings, they're either gone or dead."

And, as if having satisfied himself on this last account, Big Tim stepped directly up to the door. He was a tall man, yet he seemed dwarfed beside it. And it was obviously very massive, for it was partly open and the width of the edge revealed could not have been spanned by the long, flexible metal fingers of their protecting gloves. The opening was a mere crack, as if someone had once made it so for a cautious glimpse of the world outside and never closed it again.

Big Tim placed his gloves against the projecting edge.

"Give me a hand, Brad. We'll see if we can open it further."

Together, they shoved. They drew upon ebbing reserves of strength, but what energy they managed to summon they threw into a brief, terrific effort to move the portal. But it did not move. Their combined strength seemed pitifully small against the weight they sought to budge.

They were about to relax their efforts in despair when, suddenly, transmitted from the metal of the door to that of their gloved hands, they felt what seemed to be a coughing whir. The sound smoothed out, deepened, and became a steady hum.

Startled, they leaped away. Their faces took on an intent, incredulous expression.

The door was opening. Slowly, majestically, it was swinging wide.

No force that they could see was behind it. The door seemed to move of its own volition. They stood as still as a pair of weird, metal statues, watching. Every sense, keyed to its highest, was directed at the widening gap.

At last all movement ceased, and the door hung wide. The humming note which had accompanied its opening dwindled to a whisper and died away. Revealed was a tunnel of utter blackness.

Tim Austin released his breath. The sound roused Nellon from the trance which gripped him.

"It's probably controlled by an automatic mechanism. When we shoved against it, we must have set that mechanism in motion."

"I'm going in, Brad," Big Tim said suddenly. "I'm going to see what's inside." He strode impulsively to the door. But at the threshold he stopped and turned and looked at Nellon.

Nellon smiled faintly and nodded. He strode after Big Tim. Together they entered the doorway.

Lights, built into the helmets of their suits, but up to this time unused, were turned on to illuminate the way. The tunnel, they saw, was a rectangular corridor or passageway. It was lined with the same metal as that of the door.

At two intervals down the corridor they found it necessary to squeeze through half-opened doorways. The doors here were of the slide type and seemed to be controlled by machinery as was the one which they had opened to gain entrance to the corridor. But these could not be moved, nor did their efforts awaken any hum of machinery.

"You know," Big Tim remarked, "this arrangement of doors sort of reminds me of an airlock."

"I've noticed the same thing," Nellon responded. "But an airlock—" He shook his head, for this was one of the many things he couldn't understand.

Soon the corridor came to an end. Nellon and Austin found themselves in a small, square room, each side of which was lined with small glass cubicles or cabinets. In each reposed a transparent sphere with various inexplicable attachments and a compactly folded mass of some strange material.

"Helmets!" Big Tim breathed. "Brad, those are helmets. And unless I'm mistaken the other stuff must be suits of some kind. What have we stumbled onto, anyway?"

Nellon passed a slow, almost-knowing glance about the room, his helmet lights glinting on the glass of the cabinets.

"I've got a crazy idea," he said. "But let that wait until we see more. There's another doorway over there. Let's go on."

They went on. There were more corridors, but this time there were rooms opening from them. Each was uniformly alike, filled with the same articles and furnishings. Nothing with which they were familiar had any counterpart here. Everything, from strange, rounded furniture to bizarre clothing, was weirdly alien.

But of the beings who had once inhabited these rooms they found no trace. There were only the garments they had once worn, the chairs in which they had sat. About these clung the ghosts of their presences. Over all was an air of desertion and long neglect.

They entered another section. Here there were rooms as large as halls, spread with queer tables and chairs. One they found to be a library, for on shelves they found large, tablet-like books whose stiff pages were covered with glowing hieroglyphs.

Then they found their first stairway, a succession of small ramps leading to some floor above. They ascended slowly, with the feelings of men entering some new portion of strange and utterly alien world.

Here they found but one, huge room, and this their lights revealed to be perfectly circular. In the center, glowing greenly, was what appeared to be an immensely thick column, rising from floor to ceiling. About this banks of strange instruments and machinery were grouped.

"Brad," Big Tim whispered. "This place—What on earth could it have been for?"

Nellon made small, slow shakes of his head.

"That's what bothers me. I can't imagine any possible use. They knew utility, the beings who built these rooms. There was a good purpose for this room, I'm sure. Yet I can't imagine what it could have been. None of the activities which we normally carry on in life would seem to fit in with these surroundings."

"Brad—that's it! This room was for no normal use. It was for something—oh, I don't know. But it must have been something tremendously important to them. I feel—" Big Tim did not finish. His strained, low voice died away, and he moistened his lips. The reverie heavy upon his face showed clearly how oblivious he was of the act.

"Let's take a closer look at that column, or whatever it is," Nellon suggested. "We might find a clue."

The column was big. Just how big they had never realized. It was only when halfway to it, and still approaching, that awareness of its size began to dawn upon them.

The vastness of the room had dwarfed it somewhat, but now, almost upon it and with their own sizes as standards of comparison, they were amazed and awed at its cyclopean girth. Slow understanding of the heroic dimensions of the place in its mysterious entirety began to dawn upon them.

And then Nellon became conscious of something else besides size. With closer and closer approach to the column, a strange comfort and well-being was growing within him. The stiff soreness of his bruises was easing. The sense of restless confinement which he always associated with the wearing of his thermalloy suit was dimming. The first pangs of rising hunger of which he had earlier become aware were now dulling, as though he were in the midst of a bountiful and delicious meal. He experienced a rising tide of physical and mental satisfaction, as if every want of these two components were being realized and generously administered to.

Momentarily, he thought of Laura and, because it had grown to be synonymous with her, the murder of Big Tim. His mental picture of the girl had never been more beautiful, desirable, or appealing. Every quality which she had ever possessed, real in actuality or imaginary as a result of his idealizations, was now transcended beyond all mortal planes. She became the very embodiment of every human aspiration and desire.

Surely, he found himself reasoning with that curious pleasure and contentment which had come over him, the murder of Big Tim for so glorious and wonderful a girl could be no base act. And the scruples which had forever risen to bar him mockingly from the actual deed, were now so smoothed away that he would never have known he had had them. Big Tim would die, of course. And he would take great pleasure in killing him. There would be no regrets, no self-accusations, no torturing pangs of conscience. There would only be complete satisfaction, comfort, and happiness. And Laura would be his. There was no doubt about that. There was no doubt anywhere in his mind. There was only complete gratification of every whimsical and vagrant thought or desire.

Then a sudden jar shook him. For a moment he had the sensation of struggling up from warm, drowsy depths. And then, suddenly, he was looking into Big Tim Austin's puzzled and incredulous face, and that eery mental surcease was gone.

"Brad—did you feel it, too?"

Nellon nodded wordlessly. He was a little frightened of the weird force that had held them both in thrall. A glance at the column looming gigantically before him showed that he and Big Tim had walked a good distance without any conscious knowledge of having done so. It was the chance collision which had aroused them both from their sleep-walking state.

Nellon could feel the force yet, brushing at the fringes of his mind with warm, soothing fingers. But he soon found that, with active resistance, there was no fear of it overcoming him again. One thing persisted, however, and that was the curiously refreshed and stimulated condition of his body. Nor was he anxious that this should go away.

They were within yards of the great column, now, and at an ever shortening range their eyes began to make out certain details which they had missed during their progress under that inexplicable half-trance.

It was not actually a column, they realized, for it was hollow and they could dimly make out the shapes of objects within. It was a vast, room-like cylinder or enclosure, with walls of transparent green. In the center, and midway between floor and ceiling, there hung what seemed to be a ball of vivid green fire.

Upon reaching the cylinder, they pressed closely to its hard surface and peered intently within. But at first the great, flaming ball obscured such early details as they could discern. It was like looking upward through water at the blinding disc of the sun. Then, as their eyes grew accustomed to the emerald brilliance, they found themselves gazing at an unbelievable scene.

High above floated the fiery, green ball. Directly below it glittered the complex mass of a great machine. This was spread upon a huge base and narrowed as it rose. Circling the apex were a multitude of rod-like projections, the ends of which terminated in large crystal cones. The bases of these were pointed upward, and from each a pale, almost invisible, beam shot up and into the green ball, as though at once nourishing and supporting it.

But it was not this which held the incredulous fixity of their gaze. For arranged in concentric circles about the machine were hundreds of tables or low platforms and upon each a still figure lay. The nearest table was some distance from the wall through which Nellon and Austin peered, and this, added to the weird, green light of the globe, made a clear delineation of physical characteristics impossible. Yet they were able to make out enough to become convinced, that, as their earlier examination of the clothing in the rooms had suggested, the figures were hauntingly human.

For a long moment they stood there. Then Big Tim turned, and Nellon, looking around in response to the action, was amazed at the bright and feverish gleam in the other's eyes. Words tumbled from Big Tim's lips in a hoarse rush.

"Brad, this is going to make interplanetary history. It's the biggest thing since the discovery of the first dead city on Mars. We've got to go back to the ship and bring the others. They've got to see this. But, Brad, before they do, I'm going in there. I want to be the first to see what these people looked like. There must be a door somewhere—"

And before Nellon could voice the protest which rose to his lips, Big Tim had started away on an eager circuit of the green wall. Nellon stood looking after him in indecision, torn between conflicting impulses. Then he tightened his lips and followed in the direction which Big Tim had taken. But before Nellon could reach him, the other's excited voice crashed in his earphones.

"I've found it, Brad! There is a door here."

Nellon jerked into a run. He found Big Tim standing upon a short ramp before a section of the wall which was different from the rest. It was a dark area, rectangular in shape. At one side, seen dimly through the strange green substance, was an arrangement of rods and gears which was obviously an operating mechanism. Protruding from a slot in the wall, and clearly connected with the mechanism, was a short lever.

Big Tim's blue eyes glittered with daring. His tow hair awry, he looked more than ever the picture of an overgrown, impulsive boy.

"Good heavens, guy, you surely don't intend to go in there!" Nellon exclaimed. "We don't know what sort of—"

Big Tim gave a short, excited laugh. "Look—there's nothing to be afraid of. There's just that green light up there and the people, and they are dead. Everything in this place is dead. Brad, this is the chance of a lifetime. We'll be the first to look upon the faces of an extra-terrestrial race since the Martians."

Big Tim pulled the opening lever. There was a moment of appalled and complete quiet. Then hidden motors hummed into alien life, and slowly the door before them slid aside. Undimmed now by its confining walls, the green radiance poured through the opening in a blinding flood.

"Come on," Big Tim urged. And without any hesitation on his own part, he stepped through, to be bathed instantly in the emerald glow.

Nellon moved to the open doorway. The emerald rays from the globe fell upon him with an almost sensible warmth. Again that weird peace and comfort was upon him, but more overpoweringly now. He felt a rising tide of drowsiness. In some strange way, he knew it would be good to allow himself to succumb to the softly-blanketing darkness which was filling his mind. It would be a blessed surcease from all the troubles and cares of his present world. But something held him back.

And though a great, calm voice seemed to give him every assurance of safety, a stubborn, small one screamed him its warning. In a turmoil, he watched Big Tim stride toward the nearest of the platforms.

It became evident to Nellon almost immediately that Big Tim was never going to reach his goal. For shortly after the first several steps, the blonde giant's purposeful walk slowed to a bemused shamble. And, watching with a curiously disembodied attention, Nellon saw him waver, stop, and then collapse upon the floor, as though he had suddenly become very, very tired.

The warning voice was shrieking now. Nellon felt a swift rush of terror that ripped him free of the force which enclosed him in its lulling folds. He shot a wide-eyed glance from the gleaming, inert shape of Big Tim's suit to the globe flaming high above. He wanted suddenly to run.

He struggled in panic against the invisible bonds of peace and comfort which were so reluctant to let him go. His determination to be free was the fierce and frenzied one of utter fear. Flailing his arms as if against some material foe, he managed to stumble down from the ramp, to one side of the doorway where the green light would not reach him.

Exhausted from the herculean struggle, he slumped to the floor. A soft, warm blackness was settling over him, and he was powerless to fend it off. But he knew that he was safe, and the satisfaction which he felt was increased by the radiation which he had absorbed, so that when he finally swooped into unconsciousness, it was amidst a thunderous, victorious singing.

Nellon's next sensations were curious ones. He seemed to awaken in another realm. It was a vast and formless place with no distinguishable feature or color, but it was curiously sentient, pulsing with awesome possibilities.

Now, as though stirred by his reflection upon it, the nebulous stuff began to writhe. And then, taking shape from the formless jumble of thoughts in his subconscious, a dream-world began to grow. Bits were added here, others discarded there, but every compartment in the storehouse of his mind contributed something. And all assembled in accordance with the pattern Nellon had fashioned in two and a half years of brooding. Finally his dream paradise was complete to the last detail of his hopes and imaginings.

It was the world which he had built around Laura taken on an immaterial, but to him nonetheless real, life. There was Laura and there was himself. And there was the complete bliss for which he had planned Big Tim's murder to achieve.

He became aware of a change. The outlines of his world were dimming, dissolving, fading. Even Laura, radiantly lovely, was beginning to blur before his eyes.

In horror he sought to clutch the evaporating structure to him and stabilize it once again. But it slipped through his fingers like an impalpable mist. Before he was fully alive to it, his dream Eden was gone, and he was back in that formless void in which he had found himself. And even that was thinning.

Nellon awoke. He looked around for Laura and that idyllic dream land in which they had loved. But only the great, green cylinder with its flaming globe and the vast room beyond met his gaze.

Nellon climbed to his feet. With the action, he became aware that he felt wonderfully refreshed and stimulated. He looked around for Big Tim, then he remembered. Avoiding the open doorway through which the rays still poured, he peered through the green wall. Big Tim was lying there on the floor within. He was very still in his thermalloy suit.

Nellon began a chain of reasoning. As it progressed, there went with it a rising tide of exultation.

As long as Big Tim remained there under the influence of the globe, he would remain unconscious, living, perhaps, a dream as real and vivid as his own had been. It would be just as though Big Tim were dead. None of the expedition members knew of the doorway through which he and Big Tim had entered. With the almost continuous storms which raged on Titan, the door would soon become covered again. Ages might pass before a chance accident revealed it once more.

He, Nellon, could go back to the ship with a tale of how he had lost Big Tim in the bitter storm. The men might search, but he knew it would be futile.

Laura would grieve, of course, when he returned and told her the news. But he would be there to comfort her, and she would get over it. And he knew that she would marry him, with Big Tim out of the way. He could look forward to a happiness more satisfying than that of the dream.

Nellon saw his course clear. He knew just what he had to do.

First he released the lever, and the door slid shut, entombing Big Tim within the great cylinder. Then he retraced his way down to the lower level and through the maze of rooms and corridors. It was not long before the snow of Titan once more keened against his suit.

He threw his weight against the great door. Only the impulse was necessary to close it, for the operating mechanism hummed into vibrant life and it swung shut where it had not been shut before—and locked! Nor would it open again.

Even if he had wanted to re-enter, that was impossible.

Nellon started back to the ship. With the curious vigor he felt, the dangers and difficulties of the return trip hardly registered upon him at all. Gone was his sullen dislike of the ever-raging storm. He plowed through it with a careless smile, fighting his way over the wild and tumbled terrain. And it was with no feeling of exhaustion at all that he finally sighted the great, toothed ice ridge which marked the site of the camp.

As Nellon shouldered through the narrow cleft which led into the protected, tiny valley, he remembered to remove the smile of eager triumph upon his face. It would not go with the story he was to tell.

But it was hardly necessary for him to make the effort. For at the sight that met his eyes, an involuntary grimace of appalled amazement flashed over his features.

Where the ship had rested there now was nothing at all, save a smooth surface of snow. And to his incredulously searching gaze, there was no indication that anything had ever been here. The little valley was virgin of any sign of human habitation. Only the bitter wind existed here, as always it had, keening along glittering ice surfaces, sporting with the snow.

Nellon felt the sudden nausea and weakness of a terrible fear. But a bit of flotsam presented itself out of the turbulence of his thoughts, and he clutched at it with the eagerness of despair.

He must, he told himself, have accidentally encountered a site similar to the one in which the ship had lain. He had but to find the correct ridge and everything would be all right.

Nursing this hope, he started on a tour of the vicinity. Soon he realized, however, that there was no other ridge, and he had to face the fact that he had originally been at the real site. The only difference was that the ship was gone.

But Nellon felt that he had to make certain. Returning to the valley over which the ridge rose like a sheltering wall, he searched about in the deep snow. One of the first objects he discovered was a large, metal box. On one side were stenciled words which burned into his brain:

The Harton-Finston Institute.

He knew now beyond any lingering doubt that he was in the right place and that the ship was gone, for it was the Institute which had sponsored the expedition. And he had seen other boxes like that piled compactly in the holds of the ship.

Nellon was stunned, crushed. But out of his despair a slow wonder rose. How long had he been unconscious there beside the great green cylinder? The degree to which the snow had blotted out the litter of the camp suggested that it must have been many months. For a moment it seemed incredible that his momentary exposure to the emerald rays of the globe could have produced such a result. Then he remembered the beings, circular row upon circular row of them, lying beneath it, and an awesome knowledge flooded over him.

Those beings were not dead. Exposed constantly to the rays of the globe, they were merely held in a state of slumber, dreaming dreams, undoubtedly, just as curiously real and poignant as his own had been. They were sleeping and dreaming, and the green globe brooded over them like some vast guardian, soothing, nourishing.

And Big Tim slept with them. When they awoke, Big Tim would wake and live again. But he, Nellon, would not live again. Suddenly his fear and hate of the storm returned in full and terrible force. Because when his batteries were exhausted, his suit would cool—and the storm would kill him. Slowly, inexorably, death would come to him. And death was a sleep from which there was no awakening....